Infant Brain Development – OR – Pay Attention to My Synapses

We are buried in 4’ of snow here in the DC area. Fortunately our household has power so we are warm and I now have the time to write this post about infant brain development. The streets are deserted, the government is closed, and all is quiet. So in this silence let us go together into the infant brain.

The peak of infant brain development occurs between the ages of 0 and 2. Human growth and development, through observation and neurological research, confirms our understanding that the early years of life are of critical importance for laying the foundation for a lifetime of learning and loving.

The brain is the most immature of all organs at birth. It continues to grow and develop after birth. This growth was thought to be determined primarily by genetics. Scientists now believe it is also highly dependent upon the infant’s experiences. Research shows that interactions with other people and objects are vital nutrients for the growing and developing brain. Different experiences can cause the brain to develop in different ways. It is this “plasticity” of the brain and its ability to develop and change in response to the demands of the environment, that enable children to learn how to use computers as successfully as their ancestors learned how to hunt animals in the wild. Along with genetics there is mounting evidence that experiences affect the way genes are expressed in the developing brain. While good early experiences help the brain to develop well, experiences of neglect and abuse can literally cause some genetically normal children to become mentally retarded or to develop serious emotional difficulties.

To understand how this happens, we need to understand a bit about how the brain works. The brain is comprised of many regions that perform specific functions, such as identifying what we see, processing spoken language, or assessing danger. Within each of these brain areas are millions of neurons, or nerve cells, which send messages to each other across synapses. These trillions of nerves and synapses and the pathways they form make up the wiring of the brain.

[Synaptic Brain Density – These are the neural connections that enable the brain to do its work. They increase more rapidly in the first year of life than at any other period of human development. Dendriatic Connections – These are less ingrained by experience and repetition. They are pruned away by our bodies during the second and third years of life.]

In most regions of the brain, no new neurons are formed after birth. Instead, brain development consists of an ongoing process of wiring and re-wiring the connections among neurons. New synapses between cells are constantly being formed, while others are broken or pruned away. In early childhood the brain is genetically programmed to produce more synapses than it will ultimately use. By 8 months of age a baby may have an astounding 1,000 trillion synapses in his brain! This blooming of synapses happens at different times in different areas of the brain. Development then proceeds by keeping the synapses that are used and pruning away those that aren’t. The pruning of synapses happens over the childhood years as the different areas of the brain develop. (Huttenlocher & Dabholkar, 1997).

Pruning allows the brain to keep the connections that have a purpose, while eliminating those that aren’t doing anything. Pruning increases the efficiency with which the brain can do what it needs to do. But, because the brain operates on the “use it or lose it” rule, an “over-pruning” of these connections can occur when a child is deprived of normally expected experiences in the early years. This leaves the child struggling to do what would have come more naturally otherwise. Some areas of the brain become less “plastic” or changeable when the pruning is over. This has led to tremendous concern about providing what the brain needs to prune and organize itself correctly before the “windows of opportunity” close.

A fundamental task undertaken by infants is determining how they get their needs met in the world in which they live. They are constantly assessing whether their cries for food and comfort are ignored or lovingly answered, whether they are powerless or can influence adults. If the adults in their lives respond predictably to their cries and provide for their needs, infants will be more likely to use these adults as sources of safety and security. With safety taken care of, they can focus attention on exploring, allowing their brain to take in all the wonders of the world around them. If their needs are met only sporadically and pleas for comfort are usually ignored or met with harsh words and rough handling, infants will focus their energies on ensuring that their needs are met. They will have more difficulty interacting with people and objects in their environment, and their brain will shut out the stimulation it needs to develop healthy cognitive and social skills (Lieberman & Zeanah, 1995).

Children who receive sensitive, responsive care from their parents in the first years of life enjoy an important head start toward success. The secure relationships they develop with the important adults in their lives lay the foundation for emotional development and help protect them from the many stresses they may face as they grow. Researchers who have examined the life histories of children who have succeeded despite many challenges in their lives consistently found that these people had at least one stable, supportive relationship with an adult beginning early in life (Werner & Smith, 1992).

Increasing numbers of U.S. infants and toddlers spend hours each day in various child care arrangements because their parents work or attend school. It is critical that the care these children receive promotes their healthy growth and development. Too often child care providers are poorly trained and do not provide children with appropriate stimulation. Research has shown that in the majority of infant care arrangements in the U.S., children are not talked to and played with enough, and they do not have the opportunity to form the kind of comfortable, secure relationships with a caregiver who will promote their healthy emotional development (The Cost, Quality and Child Care Outcomes Study Team, 1995; National Center for Early Development and Learning, 1999).

As our society becomes more technically and socially complex, we cannot afford to continue to allow large numbers of children to miss out on the positive experiences they need in infancy and early childhood. The costs in terms of lost intellectual potential and increased rates of emotional and behavioral problems are too high. The new developments in brain research show us what children need; our challenge is to ensure that every child receives it.